"When his candle shined upon my head, and when by his light I walked through darkness."—Job xxix.
264. Why do tallow candles require snuffing?
Because the oxygen of the air cannot reach the wick through the body of flame—therefore the unconsumed carbon accumulates upon the wick.
265. Why do composite and wax candles not require snuffing?
Because their wicks are made by a series of plaits, by which they are bent to meet the oxygen of the air, and consumed.
266. Why does setting a glass upon a lamp increase its brilliancy, though it shortens the flame?
Because it conducts an increase of air to the flame, and the greater supply of oxygen causes the escaping vapour of oil to be all rapidly consumed.